The inhibition mechanism and performance of the alcohol amine corrosion inhibitor for the Q235 steel in the simulated pore solution of the concrete were studied by quantum chemistry calculation, molecular dynamic simulation and electrochemical test. Through the analysis of frontier orbital, the highest occupied molecular orbital(HOMO) of the alcohol amine molecules locates near the N atom and the lowest unoccupied molecular orbital(LUMO) is around the O atom. This distribution can make the corrosion inhibitor to form multi adsorption center on the metal surface and make the adsorption more stable. By analyzing the global database and molecular dynamic of the four kinds of molecular, the inhibition rate is N, N dimethyl ethanolamine>diethanolamine> propylamine> ethanolamine. The parameters that were obtained from electrochemical impedance spectroscopy(EIS) indicate that the inhibition rate is N, N dimethyl ethanolamine>diethanolamine> propylamine> ethanolamine. This is consistent with the result obtained from quantum chemistry calculations. The alcohol amine molecules can spontaneously adsorb on the steel surface. The ΔG0 is about -20kJ/mol, the mechanism of the adsorption is physisorption.